STC-1 MBT Prototype

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The name STC was used by the the Japanese media to refer to the ST-A series and STB series. However they later on changed the program title to NTK for the Type 90 meaning New Tank. The individual tanks were named TK-X-000#, TK-X-001#, TK-X-002# and so on.

But to make it easier for everyone to follow along, i be refering to the prototype as STC-1 witch was the media name used for the prototype.

First Pictures of the Type 90 prototype called STC-1

The Mitsubishi Company was tasked by the SDF to develope a new MBT for Japan to replace the aging Type 74s. A task that will give way to multitude of tank prototypes and test beds, the Tank X program (what it was called) went through a series of different designs for their Main Battle Tank candidates. The most iconic of which is STC-1 witch is one of Japans first new MBT prototypes, relying on a more sloped turret design and a Japanese made Steel Works 120mm and 135mm smoothbore cannon.

STC-1 prototype relied less on the modular composite and more on having thicker RHA plating. However once Japan mastered the techniques of composite witch made progress in the early 90’s, Japan later on decided to rely on more modular composite placements seen on the modern Type90 MBT.

STC-1 is the first prototype of what would later on becoume the Type 90 we all know and love. The STC-1was japans first atempt in developing a new modern MBT to replace the aging and outdated Type 74s. There were 2 versions (STC-1 and STC-2) that were fitted with a made in Japan cannon the 135mm Gun by Daikin Industries.

After some intensive test they changed the canon to a 120mm L/44 cannon built by Mitubishi Heavy Industries. But the SDF wanted to reduce the manufacturing costs of this new MBT, So Mitubishi instead opted for making a contract with Rheinmetal to produce thier own licensed version of the L/44 witch was mounted on the 2 later prototypes (STC-3 and STC-4).


The image on the top is the STC-1 Prototype and the image under is the Type 90, this a comparission image with key diffrences in design.

The key diffrences between the STC-1 and the Type 90 is the following:

The design of the hull of the tank is very similar to that of the Abrams tanks, and both have the driver positioned at the center. However the upper front plate of STC-1 was sloped even more then that of the Abrams tank.

As seen in the picture, the composite gloves are covered with cloth (Face armor of the turret), the current Type 90 tanks composite gloves are covered by steel. Also the smoke lunchers are mounted horizontaly exactly as in the Type 74 tanks.

There are two headlights looking parts that are mounted in the front and there is no known information for their use. Also there is no fence/“bucket” at the back of the turret like found on Type 90s, and there is a strange metal bar on the engine deck. Last but no least the size and shape of the gunner’s sight is different from that of current Type 90s.

The turret design of the STC-1 followed a similar design philosophy as the sloped Type 74s turret design, with much of the protection being offered by an 85° sloping to the turret roof which was designed to deflect shells. In addition to the armor protection found in the STC-1 would be very similar to that of Type 90 in game armor, at the front with spaced steel side turret armor. But the biggest draw back of the STC-1 is the absolutely massive mantlet which was designed to also accommodate a 135mm gun. Tho the 135mm gun was fired and tested, it was never mounted on the STC-1. They only mounted the home made 120mm smoothbore gun made by Japan Steel Works on the prototype (STC-1).

DAIKIN Industries was tasked in working on making a new APFSDS shell. The APFSDS that was used was an extremely high hardness tungsten composite alloy with a hardness scale of 39 on the Rockwell scale (Class 4 tungsten is a 31) with an elongation at break of 12.4%. With this it gave the round extreme good elasticity despite the high hardness of the round. If you combined this with the high pressure giving it a superior velocity to that of the competition allowing it to penetrate up to 500mm vertical at the distance of 2 km away. To put it simply it fired the same round fired by the Type 10!

DAIKIN Industries also developed a new HEAT-MP round based on the design features of the M431 HEAT-FS. The HEAT shell could penetrate up to 600mm of armor and travel at the speed of 1200m/s.

Both JSW and DAIKIN Industries also independently developed there own 135mm cannon (which never got to be mounted, but was tested and fired) outside of the contract given by the SDF, as a possible upgrade which was able to achieve a muzzle velocity of 2000m/s. This information was revealed by one of the lead designers on the canon at DAIKIN Industries. But there is not much more information known about the 135mm canon past it’s gun velocity.


But the biggest key diffrence between STC-1 and Type 90 is the CITV(Comanders sight), It provided the commander with a 360° view of the battlefield both day and night compared to the production Type 90 which has a fixed direction Comanders sight that only gives the commander access to about 180° of view. The CITV on the STC-1 is the same one that was mounted later on the Type 10 and the TKX. Also the gunner had two sites, normal and hot wire.

There is not so many diffrences in the back of the STC-1 from the Type 90, there is only two diffrences and that is the exhaust pipe form and the metal bar on the engine deck. But more then that there is no more major diffrences!


*Hull length: 7.5m.
*Hull width: 3.05m.
*Height: 2.34m.
*Crew: 3.
*Ground Clearance: 0.45m (adjustable between 0.2 to 0.6m
front and back)
*Weight: 50,000kg (combat)
*Ground pressure: 0.89kg/
*Max speed: 70km/h.
*Max range (internal fuel): 400km on road.
*Armament: 120mm smoothbore gun built by Japan Steel
Works and Daikin Industries
*machine gun mounted coaxially, 1 x 12.7mm (0.5) machine
gun on turret roof.

Japan is suffering the lack of vehicles in some of it’s BR’s. The STC-1 can be a good addition to the Japanese tech tree, boosting the options of vehicles in the tech tree. How it will be implemented into the game (as squadron, tech tree or premiume) is up to the developers and community.


“Journal of Defense Technology” March 2010 No.348, page 58

Galileo Publishing “Ground Power”
March 2006 issue Miharu Koze
Argonaut “PANZER”
January 1991 issue Keiichi Nogi
November 2009 issue Yusuke Tsuge
September 2016 Issue Written by Taro Kagaya
/ April 2019 issue Written by Taku Esaka
Ushio Shobo
Kojin Shinsha “Koujinsha NF Bunko” / History of tank development in postwar Japan Written by Iwao Hayashi


Absolutely yes. This tank actually sounds like a better Type 90 in terms of equipment and ammunition.

Either way very good suggestion +1


+1 yes japan need more mbt to replace the lack of spaa.Imagine that you have to face the pressure of enemy planes to send out tanks after tanks and you have no way to shoot them down on the ground. Everyone can only use tanks in exchange for bombs and missiles on the opposite side to achieve the goal of victory


I’m working on some SPAA suggestions don’t u worry! And there already exist 2 SPAA suggestions for japan. But i see your point i do, but more mbts for japan will be helpfull for japan!

Thank you for your contribution to the perfection of the Japanese tech tree.I’m looking forward to Japan’s future wins for allies with autoloaders and top-notch anti-aircraft

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The 135mm was manufactured during the development of the Type 10 and has nothing to do with the Type 90 prototype.


What this article/book is talking about is the 135mm and 120mm cannons that were both made by Daikin Industries. The 135mm one was made for the first prototype the STC-1, and the 120mm was made but adopted by the Type 10 later on.

On a side note many technologys and desgins from the STC-1 was later on put in the Type 10, why not Type 90? Well becouse they wanted to save money on the manufacturing costs of the Type 90s.

But as said both Daikin Industries and JSW made there own 135mm canons, and they were tested and fired but never mounted on the STC-1 prototype. Even the shell it fired was later on used by the Type 10s, and that’s becouse the later prototypes STC-3 and STC-4 used the Rhimetal 120mm smoothbore gun. And the Rhimetal canon was not compatible with the japanese round!

It is my understanding that the 120mm gun was produced domestically during the prototyping of the Type 90, and that during the prototyping of the Type 10, the know-how was utilized to produce a 135mm gun, and as a result, the 120mm gun was adopted for the Type 10.

Yes, u are correct on this:
“the know-how was utilized to produce a 135mm gun, and as a result, the 120mm gun was adopted for the Type 10.”

But the they allready have made 135mm canon before, becouse Japan got wind of Russia making there own 135mm canon, so being the cold war japan wanted to make there own. The STC-1 was designed to house a 135mm canon and u can see it on gun mantel.

But to wrap it up, u are correct during the STC-1 program they made a 135mm canon but never actually mounted on a turret! But they also made a scound 135mm canon during the Type 10 prototype program. The 120mm Japanese made canon was improved from the STC-1 program and later on was put on Type 10. But you are completely correct on your point :)

The information about the Russian 135mm gun is not an article, it was written by the author of this blog.
Japan developed the 135mm after the Type 90 tank was adopted.The 135mm gun was not manufactured at the time of the prototype of the Type 90
Assuming that the first prototype of the Type 90 tank was prepared to carry 135 mm, the shields of the mass-produced vehicles should have been smaller, but this has not actually changed.

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Would definitely love to see it come as a potential 10.3-10.7 MBT, and with other nations coming to Japan it could really help flush out the lineups at different BR’s for Japan


Very unique +1